Composition of metal.



UNITED STATES PATENT OFFICE.

ROBERT C. TOT'IEN, OF PITTSBURG, PENNSYLVANIA.

COMPOSITION OF METAL.

Specification of Letters Patent.

Application filed June 8, 1907.

Patented March 3, 1908.

Serial No. 377,866.

To all whom it may concern:

Be it known that I, ROBERT C. .ToTTEN, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in castings, which have heretofore been made.

principally from what is known as charcoal iron. Charcoal pig iron has generally been considered a necessity for the making of such chilled castings, the generally understood reason for this being that it is the only pig metal that contains what is termedjcom bined carbon in sufficient quantity to im part to the iron containing it the peculiarity of making a chilled surface when cast against a metal chill. One theory in regard to this combined carbon is that the carbon is chemically united or combined with the iron as distinguished from being present in graphitic form. While the demand for this charcoal pig iron has been constantly increasing, the production of the same has apparently reached its limit, largely on account of the cost of the charcoal necessary for smelting the same. By my invention I am able to produce from pig iron made by the coke and coal process, a chilling cast metal having practically the same properties as found in the charcoal pig iron, and thus to utilize a cheaper pig iron for the purpose and one of which there is abundant supply.

My invention consists, generally stated, in a new composition of chilling cast metal, consisting of coke or coal iron and carbid of silicon; the latter being the product of melting sand and carbon together in an electric .furnace, its formula being S i C, and known to the trade as carborundum. It analyzes high in carbon, and when used with melted cast coke or coal iron, gives to the metal the peculiar qualities ordinarily found in charcoal iron as above referred to.

In the manufacture of this chillin iron I melt the coke or coal iron inany suita le way, preferably in an air furnace, and either before or after the metal is drawn from the furnace, I.add to the melted iron the proper proportion of carbid of silicon to produce the proper depth of chill which may be tested while the metal is. still molten.

The ordinary coke or coal pig iron contains a large :amount of graphitic carbon and a small proportion, sometimes onl a trace, of combined carbon. Carbid of si icon contains as high as 35% of carbon. I mix the coke or coal pig iron with carbid of silicon in suitable proportions in order to obtain the requisite amount of combined carbon in the resultant casting iron, it being desired that this proportion shall be as much as onequarter of one per cent. of 1%) of carbon for strong, fine grained castings, and as.

much as one-half of one per cent. of 1%) or over for chilled rolls, car wheels, etc. I Forthis purpose I can vary the amount of carbid of silicon in any desired pro ortion, being mixed together in any suita le way to roduce a casting with suitable strengt an fineness of grain for a chilled roll car wheel and the like, the chill usually being from one-half-inch to two inches in depth. As an illustration, using coal or coke iron with say one-quarter of one per cent. of

1%) combined carbon, and carbid of silicon containing 35% of carbon, a mixture would beproduced by using 5% to 7% ofsuch carbid of silicon that would contain 1% to 2 per cent. of carbon producing a high chilling lron. In this way I am able to producea cast iron .of fine grain and great strength, adapted to produce castings of the character referred to and-especially chilled rolls, car wheels, etc.', with a hard wearing surface and the necessar strength back of the chilled surface in t e body of the roll or car wheel. As the supply of-charcoal iron is limited and-the supply of ordinary coke or coal iron practically unlimited, .1 am thus enabled to produce a cheap and suitable substitute for the ordinary charcoal iron;

WhatI claim is: fourth of one per cent. Q of 1%) of com- 1. A new composition of cast iron, bined carbon. 10 consisting of coke or coal iron an carbid of In testimony whereof, I the said' ROBERT silicon. Y Y 7 I C. TOTTEN have hereunto set my hand.

5 2. Anew composition of chil cast iron, ROBERT C. TOTTEN;

consisting of coke or coal iron on carbid of Witnesses: silicon, containing combined iron and car- JOHN R. KELLER, bon, the compositioncontainingat least one- J OHN E. WILL. 

